Commit 21e28290 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Thomas Gleixner
Browse files

x86/traps: Split int3 handler up 



For code simplicity split up the int3 handler into a kernel and user part
which makes the code flow simpler to understand.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarAlexandre Chartre <alexandre.chartre@oracle.com>
Link: https://lkml.kernel.org/r/20200505135314.045220765@linutronix.de
parent 8edd7e37

arch/x86/kernel/traps.c

+40 −28
Original line number Diff line number Diff line
@@ -568,6 +568,35 @@ exit: 
	cond_local_irq_disable(regs);

}



static bool do_int3(struct pt_regs *regs)

{

	int res;



#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP

	if (kgdb_ll_trap(DIE_INT3, "int3", regs, 0, X86_TRAP_BP,

			 SIGTRAP) == NOTIFY_STOP)

		return true;

#endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */



#ifdef CONFIG_KPROBES

	if (kprobe_int3_handler(regs))

		return true;

#endif

	res = notify_die(DIE_INT3, "int3", regs, 0, X86_TRAP_BP, SIGTRAP);



	return res == NOTIFY_STOP;

}



static void do_int3_user(struct pt_regs *regs)

{

	if (do_int3(regs))

		return;



	cond_local_irq_enable(regs);

	do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, 0, 0, NULL);

	cond_local_irq_disable(regs);

}



DEFINE_IDTENTRY_RAW(exc_int3)

{

	/*
@@ -585,38 +614,21 @@ DEFINE_IDTENTRY_RAW(exc_int3) 
	 * because the INT3 could have been hit in any context including

	 * NMI.

	 */

	if (user_mode(regs))

	if (user_mode(regs)) {

		idtentry_enter(regs);

	else

		nmi_enter();



		instrumentation_begin();

#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP

	if (kgdb_ll_trap(DIE_INT3, "int3", regs, 0, X86_TRAP_BP,

				SIGTRAP) == NOTIFY_STOP)

		goto exit;

#endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */



#ifdef CONFIG_KPROBES

	if (kprobe_int3_handler(regs))

		goto exit;

#endif



	if (notify_die(DIE_INT3, "int3", regs, 0, X86_TRAP_BP,

			SIGTRAP) == NOTIFY_STOP)

		goto exit;



	cond_local_irq_enable(regs);

	do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, 0, 0, NULL);

	cond_local_irq_disable(regs);



exit:

		do_int3_user(regs);

		instrumentation_end();

	if (user_mode(regs))

		idtentry_exit(regs);

	else

	} else {

		nmi_enter();

		instrumentation_begin();

		if (!do_int3(regs))

			die("int3", regs, 0);

		instrumentation_end();

		nmi_exit();

	}

}



#ifdef CONFIG_X86_64

/*

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